As a conventional direct-current power supply device that raises a direct-current output voltage to be higher than an alternating-current power supply voltage, there is a direct-current power supply device having a rectifying circuit configuration of a passive type for generating a voltage three times as high as an alternating-current input voltage (see, for example, Patent Literature 1).
There is also a direct-current power supply device that switches double voltage rectification and full wave rectification to reduce a loss of switching means and varies a direct-current voltage (see, for example, Patent Literature 2). There are other direct-current power supply devices that switch the double voltage rectification and the full wave rectification (see, for example, Patent Literature 3).
Further, there is a direct-current power supply device that varies a voltage from a peak value of an alternating-current voltage to a voltage about four times as high as the peak value (see, for example, Patent Literature 4).